Soybean phosphatidylcholine vesicles containing plant sterols: a fluorescence anisotropy study

The typical plant sterols (sitosterol, stigmasterol and campesterol) were compared with respect to their ability to regulate membrane fluidity of soybean phosphatidylcholine (PC) vesicles. Fluidity changes were monitored by the steady-state fluorescence anisotropy with 1,6-diphenyl-1,3,5-hexatriene as a probe and assigned to a measure of the acyl chain orientational order. Sitosterol and campesterol appear to be the most suitable sterols in ordering the acyl chains of soybean lecithin bilayers, even more efficient than cholesterol, the standard of reference for sterol effects on membranes, suggesting that they play a significant role in the regulation of plant membrane properties. Stigmasterol is shown to be much less active. Cycloartenol, a biosynthetic precursor of plant sterols, increases the acyl chain order with the same efficiency as cholesterol. We also investigated the effects of two unusual sterols, 24-methylpollinastanol and 14 alpha,24-dimethylcholest-8-en-3 beta-ol, which were shown to accumulate in plants treated with fungicides belonging to two important classes, N-substituted morpholines and triazoles, respectively. These two sterols exhibit a behavior very similar to that of stigmasterol. The results are discussed in terms of sterol effects on the molecular packing of soybean PC bilayers.     

Significance of saliva for the denture‐wearing population

This paper summarises a series of studies already published in German and presents new data related to the aetiology of the dry mouth' and its associated problems. Aims: to study factors affecting mucous and serous salivary gland secretion, the aetiology of the ‘dry mouth’ and its associated problems, causative factors for hyposalivation and it's treatment Setting : two university dental hospitals. Subjects: 587 denture wearers and 521 control subjects, and autopsy material Interventions : exercise, chewing, water, oestrogen, pilocarpine, and anetholtrithion theiapy, biopsy of the minor glands Main outcome measures : Palatal secretion (PAL, μL/cm²/min) and parotid salivary flow (PAR), subjective complaints and clinical findings. Results: resting flow rates for PAL between 0 and 65 μl/cm²/min were seen in every age group. The flow rates of PAR (0 to 3.7 ml/10 min) were not correlated with PAL. Most patients with a resting flow rate of PAL≤6.0 μl/cm² suffer from a ‘dry mouth’ and Burning Mouth Syndrome (BMS) or oral dysaesthesia (OD) with or without chronic lesions of the oral mucosa. Etiological factors for the incidence of reduced PAL and associated problems include xerostomic drugs, oestrogen deficiency, ladiotherapy, thyroid dysfunction, smoking or continuous wearing of complete upper dentures. PAL also correlated with the retention of upper complete dentures. PAL was correlated with the water content of epithelial tissues. PAL and PAR were both increased by drinking ample fluid, improving their circulation by physical exercises, chewing intensively, or taking oestrogens, pilocarpine, anetholtrithion. Conclusions: Variation in palatal salivary secretion occurs and is clinically important.     

Potential side effects of insect-resistant transgenic plants on arthropod natural enemies.

Engineering genes encoding insecticidal proteins into crop plants offers numerous benefits to agriculture. However, like many conventional insecticides, this new technology has the potential to disrupt natural biological control through both direct and indirect side effects of the plants on the fitness or behaviour of arthropod predators and parasitoids. Interactions between transgenic plants and these beneficial insects are being assessed to avoid incompatibility.